.dat file format of Fallout: PHP parsing library

<?php
// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild

namespace {
    class FalloutDat extends \Kaitai\Struct\Struct {
        public function __construct(\Kaitai\Struct\Stream $_io, \Kaitai\Struct\Struct $_parent = null, \FalloutDat $_root = null) {
            parent::__construct($_io, $_parent, $_root);
            $this->_read();
        }

        private function _read() {
            $this->_m_folderCount = $this->_io->readU4be();
            $this->_m_unknown1 = $this->_io->readU4be();
            $this->_m_unknown2 = $this->_io->readU4be();
            $this->_m_timestamp = $this->_io->readU4be();
            $this->_m_folderNames = [];
            $n = $this->folderCount();
            for ($i = 0; $i < $n; $i++) {
                $this->_m_folderNames[] = new \FalloutDat\Pstr($this->_io, $this, $this->_root);
            }
            $this->_m_folders = [];
            $n = $this->folderCount();
            for ($i = 0; $i < $n; $i++) {
                $this->_m_folders[] = new \FalloutDat\Folder($this->_io, $this, $this->_root);
            }
        }
        protected $_m_folderCount;
        protected $_m_unknown1;
        protected $_m_unknown2;
        protected $_m_timestamp;
        protected $_m_folderNames;
        protected $_m_folders;
        public function folderCount() { return $this->_m_folderCount; }
        public function unknown1() { return $this->_m_unknown1; }
        public function unknown2() { return $this->_m_unknown2; }
        public function timestamp() { return $this->_m_timestamp; }
        public function folderNames() { return $this->_m_folderNames; }
        public function folders() { return $this->_m_folders; }
    }
}

namespace FalloutDat {
    class Pstr extends \Kaitai\Struct\Struct {
        public function __construct(\Kaitai\Struct\Stream $_io, \Kaitai\Struct\Struct $_parent = null, \FalloutDat $_root = null) {
            parent::__construct($_io, $_parent, $_root);
            $this->_read();
        }

        private function _read() {
            $this->_m_size = $this->_io->readU1();
            $this->_m_str = \Kaitai\Struct\Stream::bytesToStr($this->_io->readBytes($this->size()), "ASCII");
        }
        protected $_m_size;
        protected $_m_str;
        public function size() { return $this->_m_size; }
        public function str() { return $this->_m_str; }
    }
}

namespace FalloutDat {
    class Folder extends \Kaitai\Struct\Struct {
        public function __construct(\Kaitai\Struct\Stream $_io, \FalloutDat $_parent = null, \FalloutDat $_root = null) {
            parent::__construct($_io, $_parent, $_root);
            $this->_read();
        }

        private function _read() {
            $this->_m_fileCount = $this->_io->readU4be();
            $this->_m_unknown = $this->_io->readU4be();
            $this->_m_flags = $this->_io->readU4be();
            $this->_m_timestamp = $this->_io->readU4be();
            $this->_m_files = [];
            $n = $this->fileCount();
            for ($i = 0; $i < $n; $i++) {
                $this->_m_files[] = new \FalloutDat\File($this->_io, $this, $this->_root);
            }
        }
        protected $_m_fileCount;
        protected $_m_unknown;
        protected $_m_flags;
        protected $_m_timestamp;
        protected $_m_files;
        public function fileCount() { return $this->_m_fileCount; }
        public function unknown() { return $this->_m_unknown; }
        public function flags() { return $this->_m_flags; }
        public function timestamp() { return $this->_m_timestamp; }
        public function files() { return $this->_m_files; }
    }
}

namespace FalloutDat {
    class File extends \Kaitai\Struct\Struct {
        public function __construct(\Kaitai\Struct\Stream $_io, \FalloutDat\Folder $_parent = null, \FalloutDat $_root = null) {
            parent::__construct($_io, $_parent, $_root);
            $this->_read();
        }

        private function _read() {
            $this->_m_name = new \FalloutDat\Pstr($this->_io, $this, $this->_root);
            $this->_m_flags = $this->_io->readU4be();
            $this->_m_offset = $this->_io->readU4be();
            $this->_m_sizeUnpacked = $this->_io->readU4be();
            $this->_m_sizePacked = $this->_io->readU4be();
        }
        protected $_m_contents;
        public function contents() {
            if ($this->_m_contents !== null)
                return $this->_m_contents;
            $io = $this->_root()->_io();
            $_pos = $io->pos();
            $io->seek($this->offset());
            $this->_m_contents = $io->readBytes(($this->flags() == \FalloutDat\Compression::NONE ? $this->sizeUnpacked() : $this->sizePacked()));
            $io->seek($_pos);
            return $this->_m_contents;
        }
        protected $_m_name;
        protected $_m_flags;
        protected $_m_offset;
        protected $_m_sizeUnpacked;
        protected $_m_sizePacked;
        public function name() { return $this->_m_name; }
        public function flags() { return $this->_m_flags; }
        public function offset() { return $this->_m_offset; }
        public function sizeUnpacked() { return $this->_m_sizeUnpacked; }
        public function sizePacked() { return $this->_m_sizePacked; }
    }
}

namespace FalloutDat {
    class Compression {
        const NONE = 32;
        const LZSS = 64;
    }
}